706 and 862 heads, are they interchangeable?

2003 CHEVROLET SILVERADO
236,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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HD1200
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I’m rebuilding my 5.3 ls engine in my truck listed above 1500. I have one 706 head that has been rebuilt and one 862 head that has been rebuilt. Are they exactly the same only difference is in casting? I’ve seen online that they are but also 862 has higher compression. So, I am not sure if that would work and if I should get another 706 or 862 head to make the heads match but I'm trying to do budget build.

Thanks
Nov 21, 2023 at 4:39 AM
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MONSTERTRUCKDADDY
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Hello HD1200,

If the combustion chambers CC are the same, and the spring installed heights are the same, and the pushrods end up being the same... you might be able to get away with it on a budget build. It's a lot of work to get to that point to find out you may need another 862.

Are you sending them out for any machine work? I'm guessing 'budget' build indicates "no".

Here's a great article that spells out the differences:

https://www.alliedmotorparts.com/blogs/news/are-862-heads-a-better-choice#:~:text=While%20862%20heads%20are%20sand,between%20706%20and%20862%20heads.

Nov 21, 2023 at 7:10 AM
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HD1200
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Okay, thanks.
Nov 21, 2023 at 8:27 AM
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STRAILER
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Nov 23, 2023 at 8:59 AM